Tuning indicator



Feb. 118, 1936. A. AGRICOLA 2,033,295

TUNING INDICATOR Filed April 22, 1955 3a O r K v INVENTOR A. AGRICOLA 4BY 3 ATTORNEY Patented Feb. 18, 1936 PATENT OFFICE;

2,031,295 TUNING- INDICATOR Alfredngricola, Berlin-Tempelhof,Germany,.as-r slgnor-toAllgcmeine ElektricitatnBerlin,Germany, a corporation ofGermanyv Application: April 22, 1935, SerialNo, 17,653 In Germany-April18,1;19341 5 Claims. v(Cl. 1161-1241).

Theinventionis concerned with. the indicator meansmsed: in' the tuningofbroadcastereceiver sets; Scale 'arrangementsare' known in the prior.

art in whichzthe-station :names or marks or the like-identifyingthe.latter are provided in any arbitraryaaorder; i: e'., in an arrangementindependent-Jot the wave-length corresponding thereto, sayguin analphabetic disposition or in the shape ofageographicalmap o-r'chart.Such a map is shownsby wayof example in-Fig. 1. The

station names I, 2, 3, 4, are disposedupon a map in accordance withtheir geographical situation; thatwis to say, eachstation being marked,for

instance, by'a circular hole'in a/map the rest of which'issopaqueywhereas posteriorlyof l the said map thereis a diskor a: filmbeing in coupling relationship: with" the tuning means and which.

upon-actuation of the tuning means. is causedto travel'posteriorly ofthe map.- Now, upon this n'iarkinghoncovering disk are arranged circularopenings'in'such'a'way that as soon; as the tuning element has been setto a definite. wave-length, the opening-in the map-which: corresponds tothe station in question-will be caused to be illumi-v nated'bywthe lampdisposed in the rear of the covering: or masking plate; in other words,the

openingsfin the latter plate are so arranged that each time theapparatus'is set'to a station, the opening of the cover plate-or maskingfilm comes to register or coincide with the, corresponding aperture in.the map:- The indication in scales of this kind could be also chosen insuch-a way-that the appearance-of a; definite mark-,say, .a smallcolored circle whichis disposedupon the plate or film arranged'posteriorly of the map, manifests in theopening provided in the map thestate of tuning to the wave-length of the station in ques- I 1 tionwhich isco-ordinated to such :opening.

In thecase of such or similar scales in which the stationnamesare-disposed not in accordance with the wave length, but in accordancewith some other orderor disposition independent'therefrom likelihood ofthis happening is particularly great whenever the number of stations onthe map is very large or when the surface or area available tion name inquestion in the alphabet, whereas point corresponding to this samestation.

Fig. 1 is a: perspective view'of a tuning indies.

cator madeaccording. to the invention and,

Fig; 2-is a partial section through the device of 1 Fig. 1 and alsoshowing a wave change switch exactly in the line of motion of thehorizontally moved marking film or strip M. Upon the move-' ment of thefilm .M which carries the opening 3a v for station 3, and opening litfor station 4', sta-- tions 3 and 4 are caused to fiashup-twice. Thestation .3 flashes .up once when thev opening 3a 1 registers with theopening 3, but again when the opening 411 coincides with the opening 3.Similar: 15; ly, station 4 will flash once when the opening :3a comestobe in registry with the opening'4; and the secondtime when theopening, 4a registers with openingd; No clearecut'andreliable tuning -ofthe receiveriset to .one of the desired stations is- 20 fortheaccommodation of a map is very limitedwith' the resultthat thebroadcast stations seem to be crowded together. 30

Now, these difficulties are obviated according to this invention by thatthe indication-of the tuned condition of a tuning element to a certain vstation is not insured by the coincidence. or registry of merely twomarking points, but of at least 3 threesuch points, of which one isfixed, e. g., in a geographic scale in accordance with the position uponthemap or in an alphabetical arrangement. in'accordance with theposition of the stafor indication of setting of the tuning element tothe :station in question by the movement of the setting means at leasttwo additional marking I points are caused to register with the markingAs 15 shown in Fig. 2 in more detail, this is accom-.. plished in themanner that posteriorly of the I map L bearing the identifications ormarkings for the stations, there is provided an endless band or web Mwhose width is chosen to suit the width of the map, the said band Mbeing conveyed over the drums I and II which are associated with thetuning means such as the rotor plates of condenser 5 by means of anytype of well known type of gearing.

Now, in the band M which is opaque the openings 3a and 3b are providedat such places that upon adjustment of the tuning means to thewave-length of station 3 the two openings 3a and 31) come to lie in astraight line with the opening 3 in the map as shown in Fig. 2. Then theopening corresponding to station 3 will be illuminated by the lamp 6disposed at the rear of the band. Hence, in this arrangement, a stationsuch as 4 in the scale L will not yet be caused to flash up if, forinstance, only one opening of the band M happens to be in registry withthe corresponding station; on the contrary, in order that this mayhappen it is necessary that two openings in the band M, being caused tomove as a result of the actuation of the tuning element, come tocoincide with the opening in the map L. As a result, as will thus beseen, in an arrangement as just disclosed, the station 4, which asrepresented in Fig. 1 is at the same level as the opening 3a on theband, will not be caused to flash up if upon the movement of the band Mthe opening 3a comes to register with the opening 4; for in thisposition, the opening 32) will not coincide with openings 3a and .4. Onthe contrary, a flashing up of the station hole in an arrangement ashere disclosed will be feasible at all only whenever three openingshappen to be in direct registry. In this disposition therefore, theindication of the tuned state of each station to the correspondingwave-length will be clear-cut and free from errors or doubts.

If in the same set the same tuning element is provided for severalwave-lengths or bands as is true of the majority of broadcast receiversets, then, in an arrangement as chosen, the stations of each wave-bandupon each and any actuation of the tuning element will be caused toflash up whenever the tuning means is adjusted to the correspondingwave-length, though during the movement of the tuning means also thestations of the other wave-bands will flash up to which the set is notadapted or connected. Now, in order that unnecessary flashing of stationnames or the marks corresponding thereto may be avoided in so far as theundesired wave-bands are concerned, the arrangement according to anotherobject of the invention may be further provided between scale L and themask M with a cover plate B which is so shaped that only the stationnames pertaining to one wave-length range or band will be illuminated.For this purpose the said screen disk or plate B may be coupled with thewave-band switch so that, when a change is made from one to other bandsthe same is caused to occupy different positions. Upon the said plateare openings at places, for instance, for the station 3 the opening 30,so that only in the position of the said plate corresponding to thewave-band that is desired the openings of the said plate will come inregistry with the openings of the stations of the same band, while theopenings of the stations pertaining to other wave-bands will be coveredup. As will thus be seen, when operating the tuning means the stationsof the wave-band concerned will be caused to flash up.

As shown in Fig. 2 the plate B is shown connected by a link 6 with thewave change switch 1 which is associated with a resonant circuit of thereceiver and comprising the tapped transformer coil 8 and the tuningcondenser 5, the incoming radio signal frequency being applied to theterminals 9 of the transformer in any known manner.

Having described my invention, what I claim as novel and desire tosecure by Letters Patent is:

1. In a device for indicating the position of a tuning means thecombination of a movable member connected to said tuning means andprovided with a plurality of apertures, a stationary member providedwith a plurality of apertures, and a source of illumination behind saidmovable member, at least one of the apertures of said stationary memberbeing in alignment with two apertures of said movable member when saidtuning means is adjusted to a desired frequency.

2. In a device for indicating the position of a tuning means, thecombination of a movable member connected to said tuning means andprovided with at least two apertures arranged to move in oppositedirections upon adjustment of said member, a stationary member providedwith a plurality of apertures corresponding to desired stationpositions, and a source of illumination behind said movable member, twoof the apertures in said movable member coming into alignment with anaperture in said stationary member when said tuning means is adjusted toa desired frequency.

3. In combination, a resonant circuit including means for tuning saidcircuit, a wave change switching device arranged to change the tuningrange of said circuit from a higher to a lower frequency band, aflexible indicating means having oppositely movable adjacent portionsconnected to said tuning means arranged to indicate the resonantcondition of said circuit and a device for screening said indicatingmeans connected to said switching device.

4. In combination, a resonant circuit including adjustable means fortuning said circuit, a wave change switch arranged to change the tuningrange of said circuit from a higher to a lower frequency band, anindicator having a plurality of apertures therein connected to saidtuning means, a member having a plurality of apertures therein arrangedto be successively in alignment with the apertures of said indicator anda screening member connected to said wave change switch and mountedbetween said last named member and said indicator said screening memberbeing provided with a plurality of apertures simultaneously in alignmentrespectively with certain of the apertures in said member.

5. An indicating mechanism for a radio apparatus or the like comprisingin combination, a relatively movable map and masks, a source of lightrearwardly of said masks, the said map and masks being provided withapertures which are registerable with one another when the said map andmasks are in a certain position and means to move the map and maskssimultaneously relative to one another whereby certain apertures of themasks are brought into register with one another and with a certainaperture of the map.

ALFRED AGRICOLA.

